Formal pathogenesis, average age and breed distribution in the comparison of 61 Lysodren-treated and 36 untreated cases of canine hyperadrenocorticism which were dissected in the years 1975 to 1991 at the Institute for Veterinary Pathology of the Free University of Berlin]

61 Lysodren -treated dogs with hyperadrenocorticism are compared with 36 untreated dogs with the same disease. 75.14% of the treated dogs had pituitary-dependent-hyperadrenocorticism (PDH) whereas this diagnosis was found in 63.89% of the untreated dogs. A functioning adrenocortical tumor (FAT) was found in 13.11% of the treated dogs but was evident in 22.22% of the untreated dogs. Simultaneous pituitary and adrenal Cushing's syndrome (PDH/FAT) were found in 11.48% of the treated and 8.33% of the untreated cases. Sex distribution was equal in both groups. Overall slightly more females than males were affected by the disease. Poodles (38.14%) and dachshunds (23.71%) were the mainly affected races. Race-distribution of diseased animals is compared to the overall race-distribution in a ten years statistic (1981-1990) of all necropsied animals (Walter und Schwegler, 1992). The mean age of Lysodren -treated dogs with a PDH diagnosis (10.0 years) is lower as the mean age of untreated dogs with the same diagnosis (10.3 years). Reasons for this unexpected finding are discussed.